fix: prevent model from inferring project names on create_task/create_note

The model was hallucinating project names from task/note content (e.g.
inferring "Vehicle Maintenance" from "purchase wheel bearings"). Added
explicit guidance to both project field descriptions: only set if the
user explicitly named a project, never infer from content.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/fabledassistant/services/tools.py

@@ -101,7 +101,7 @@ _CORE_TOOLS = [
                     },
                     "project": {
                         "type": "string",
-                        "description": "Optional project name to assign this task to",
+                        "description": "Optional project name to assign this task to. Only set this if the user explicitly named a project. Do NOT infer a project from the task content or context.",
                     },
                     "parent_task": {
                         "type": "string",
@@ -147,7 +147,7 @@ _CORE_TOOLS = [
                     },
                     "project": {
                         "type": "string",
-                        "description": "Optional project name to assign this note to",
+                        "description": "Optional project name to assign this note to. Only set this if the user explicitly named a project. Do NOT infer a project from the note content or context.",
                     },
                     "confirmed": {
                         "type": "boolean",